The insulated-gate bipolar transistor (IGBT) is a three-terminal power semiconductor device primarily used as an electronic switch and in newer devices is noted for combining high efficiency and fast switching. The IGBT can be viewed as a device with Metal-Oxide-Semiconductor input characteristics and bipolar output characteristics that is a voltage-controlled bipolar device. In short, the IGBT is essentially a combination of a Power MOSFET and a Bipolar Junction Transistor (BJT). Specifically, the IGBT combines the simple gate-drive characteristics of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with the high-current and low-saturation-voltage capability of BJTs. The IGBT combines an isolated gate FET for the control input, and a bipolar power transistor as a switch, in a single device.
IGBTs are continuing to find new fields of application. In particular, IGBTs can be found in power electronics, such as Pulse Width Modulated (PWM) servo and three-phase drives requiring high dynamic range control and low noise. IGBTs are also found in Uninterruptible Power Supplies (UPSs), Switched-Mode Power Supplies (SMPS), and other power circuits in which high switch repetition rates are required. Further still, IGBTs can be used in resonant-mode converter circuits.